1. Field of the Invention
This invention relates to a stretcher on which a patient can ride and with which the patient can be moved. In particular, this invention relates to the stretcher which is equipped with a head rest on the part that supports the head of a patient.
2. Description of the Related Art
A stretcher which can carry a patient who has difficulty getting up by himself or an older person (in this Description, they are simply called the xe2x80x9cpatientxe2x80x9d), has been used. Using a stretcher, it is possible to move the patient while he is lying on his back just as in a bed, and also it can be changed to the seating position by making the stretcher into the shape of a chair.
Also, the stretcher which is equipped with a head rest on the part that supports the head of the patient, and of which both the angle and the depth (the height when used as a bed) of the head rest can be adjusted, so that it can offer a relaxed posture for the user, has been used. The mechanism to make this type of adjustment is constructed by including a link such as a support arm, etc., between, for example, the head rest and the back support part.
In such an adjusting mechanism, namely in the angle adjusting mechanism or the positioning mechanism, the angle or the position must be fixed except during the angle adjusting time or during the depth adjusting time. Therefore, for example, a rotation prevention mechanism, etc., which utilizes the frictional force of tightening a multi-layered clutch plate, has been used.
However, according to the existing rotation prevention mechanism as described above, multiple rotation prevention mechanisms are provided individually for each rotating kinetic pair (namely, the rotating pair between the frame and the support arm, and the rotating pair between the support arm and the head rest). Therefore, each mechanism must be adjusted individually. For instance, in the case when both the depth of the head rest and the angle must be adjusted, first, the depth is adjusted and it is fixed in the desired position, and thereafter, the angle is adjusted and fixed, thus, it must be adjusted step-wise. In addition, even in the case when only the depth is adjusted, the angular adjustment becomes necessary accompanying that, and, thus, the adjustment procedure often requires extra work. In addition, the angle adjusting mechanism and the positioning mechanism each need a rotation prevention mechanism, so that there is a disadvantage for reducing the number of parts or making it of a smaller scale, also.
Therefore, the objective of this invention is to offer a stretcher in which the depth adjustment of the head rest and the angle adjustment can be done at the same time.
In order to achieve this objective, the invention is a stretcher that is equipped with:
a first shaft that is fixed onto the frame of the said stretcher;
a second shaft that is provided on the head rest;
a support arm that is installed on the first shaft in the way that it can rotate, and also that supports the second shaft in the way that it can rotate;
a rotation prevention member that has a sloped part that can be pressed when it receives a pressing force, and the pressing part that is pressed onto the circumference surface of the first shaft or the second shaft, and which can come near to or separate from the first shaft or the second shaft;
a wedge shaped member that has a sloped pressing part that presses while sliding on the being pressed sloped part of the said rotation prevention member, and which presses the rotation prevention member onto the first shaft or the second shaft by the wedge action caused between this pressing sloped part and the being pressed sloped part;
and the means to apply the load which adds a load onto the said wedge shaped member and also which maintains the state in which the first shaft and the second shaft are tightened;
and in which the angle around the first shaft of the support arm and the angle of the head rest to this support arm can be fixed at the same time, in the stretcher that has a head rest for supporting the head of the patient.
In this stretcher, the support arm can rotate around the first shaft, and also, the head rest can rotate around the second shaft that is supported by this support arm. And, when a load is not added via the load adding means, or when the load is small even if it is added, both shafts can rotate relative to the support arm, so that the angle around the first shaft of the support arm and the angle of the head rest to the support arm can be adjusted. Therefore, the depth of the head rest and the angle can be adjusted.
On the other hand, in the case when a sufficient load is applied on the wedge shaped member, the wedge shaped member is pressed onto the rotation prevention member side. At this time, the pressing sloped part of the wedge shaped member presses while sliding the being pressed sloped part of the rotation prevention member, and by the action of the wedge, namely, the action of obtaining a large force with a small stroke by transferring the pressing force via both sloped parts, these rotation prevention members are powerfully pressed onto each shaft. As a result, each shaft is tightened between the rotation prevention member and the support arm, and the rotational movement relative to the support arm is prevented. In addition, the action to attain this rotation prevention is not done in sequence for each shaft but is done together at the same time for both shafts by operating the load adding means on the wedge shaped member, therefore, the depth adjustment of the head rest and the angle adjustment can be done simultaneously. In addition, at this time, it also becomes possible to prevent the relative rotation of each shaft at the same time by squeezing the shafts at almost the same time.
In the stretcher, the first shaft and the second shaft are in parallel, and the rotation prevention member is comprised of a pair of members that press these shafts from the inside to the outward direction, and the wedge shaped member is such that its sloped pressing part has a trapezoidal shape that is comprised of a pair of sloped flat surfaces or surfaces that are similar to that, and which exists between a pair of rotation prevention members, and which presses the two shafts to the outside by being loaded by the load applying means.
In this case, when the load is applied on the wedge shaped member, the rotation prevention members on both sides are pressed toward the outside by the wedge action caused between the sloped parts, and it tightens the shaft between the pressing parts of this rotation prevention member and the support arm. By this, the relative rotational movement of the two parallel shafts to the support arm is prevented at almost the same time, or it can allow movement at almost the same time by removing the load.
A stretcher equipped with a head rest to support the head of the patient is equipped with:
a first shaft that is fixed onto the frame of the said stretcher;
a second shaft that is provided on the head rest;
a support arm that is installed on the first shaft in a way that it can rotate, and also that supports the second shaft in a way that it can rotate;
a wedge shaped member which can move in the direction to contact to the first and the second shafts, and which presses each shaft directly or indirectly by the wedging action on the sloped surfaces, and by this wedging action, it tightens these shafts between it and the support arm and prevents the relative rotation;
and means to apply the load which adds a load onto the said wedge shaped member in the direction of pressing the first and the second shafts, and also which maintains the state in which each shaft is tightened, and in which the angle around the first shaft of the support arm and the angle of the head rest to this support arm can be fixed at the same time.
In the case when a sufficient load is applied to the wedge shaped member, the wedge shaped member moves in the direction in which the load is working, and it directly presses the shaft on the sloped surface. As a result, each shaft is tightened between the wedge shaped member and the support arm, and it becomes unable to rotate relative to the support arm. In addition, the action to attain this rotation prevention does not need to be done in sequence per each shaft but it can be done together at the same time for both shafts by operating the load adding means or the wedge shaped member, therefore, the depth adjustment of the head rest and the angle adjustment can be done simultaneously. In addition, at this time, it also becomes possible to prevent the relative rotation of each shaft at the same time by squeezing the shafts at almost the same time.
In the stretcher, the load applying means is a nut and bolt, and the penetrating hole that allows the screw part of the bolt to pass through is provided on one side surface of the support arm and the wedge shaped member. By tightening this nut and bolt, the load can be applied gradually to the wedge shaped member to tighten the shaft. Also, since the cases of loosening the nut and bolt are naturally rare, it is easy to maintain the condition of preventing the relative rotation of the shafts.
In the stretcher, the wedge shaped part has a concave part that keeps the head of the bolt or the nut in a way that it cannot rotate. Therefore, the slipping of the boltxe2x80xa2nut will not occur, and it can be securely tightened or released by rotating the side which is not kept in the concave part.
In the stretcher, the first shaft and the second shaft are in parallel, and one of the above mentioned penetrating holes provided on one side surface of the support arm and on the wedge shaped member is made to be a long hole that extends to both these shafts, and the wedge shaped member is made to be able to come near to or to separate from both shafts. In this case, the wedge shaped member can move just by the stroke of the long hole. Therefore, even in the case when the deviation is caused between the pressing force on one rotation prevention member and the pressing force on the other rotation prevention member, this deviation can be absorbed by the wedge shaped member by stroking to either one, and the pressing force becomes uniform, and these rotation prevention members are pressed to each shaft by almost equal forces. Therefore, both shafts become incapable of relative rotation at almost the same time, and they can become capable of allowing relative rotation at almost the same time.